Re: R1155 restoration
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The HT neg does not go to ground but is above gnd so giving the heg bias. See pic.?
The audio amp is not needed, I simply use an o/p transformer wired backwards and an l.s. to it, more than enough audio for room listening.? ?Pin 5 straight to af o/p tranny, other side to ground.
Ben
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From: radtone999 <radtone@...> To: [email protected] Sent: Sat, 9 Jan 2021 15:54 Subject: [T1154-R1155] R1155 restoration Hi All, I have just about come to the end of my R1155 restoration; haven't used it since the late 8o's I don't know what happened to the original power supply I made for it at the time, probably pinched bits for another project. Anyway, I have made another with negative bias built in as shown on various diagrams,something I didn't concern myself with back then. But there was a massive resistor that was not stock wired in which got very hot, so perhaps that was the bias; wish I had noted where exactly it was wired Ht- to LT- perhaps? Anyway, doing a HT power test through a variac on reaching 100 volts? R4 tuned into toasted smoke. I will have to recheck the wiring on this board, but wondering if this? is a biasing issue?
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